1. Field of the Invention
The present invention relates to a terminal which has a wireless communication function, can operate using power supplied from an external power supply, and can operate using power of a battery when no power is supplied from the external power supply, and a standby operation control method which is applied to the terminal.
2. Description of the Related Art
Terminals (a PDA, portable computer, and the like) each having a wireless communication function such as Bluetooth® or wireless LAN (Local Area Network) have recently come into widespread use.
A terminal having a wireless communication function can be used all the time in a standby state wherein it waits for signals through the wireless communication function. In the standby state, however, the battery power is rapidly consumed. For this reason, in a terminal of this type, the user manually starts/stops standby operation.
In many cases, a charger is equipped with such a terminal whose battery power is rapidly consumed. For example, Jpn. Pat. Appln. KOKAI Publication No. 2002-291034 discloses that a portable communication terminal is charged by a charging circuit on the charger side when the portable communication terminal is connected to the charger. This reference also discloses that each of the portable communication terminal and charger is provided with a wireless communication interface unit. When the portable communication terminal is out of reach of weak radio waves from the charger, or it is determined that the portable communication terminal is out of reach, voltage supply to the wireless communication interface units is cut off to deactivate the wireless communication interface units, thereby reducing the current consumption.
However, a conventional terminal is arranged to start/stop the standby operation by manual operation of the user and is inconvenient. The technique of the above-mentioned reference needs a wireless communication interface unit also on the charger side and thus results in high cost. Also, the technique cannot satisfactorily meet user demands.
For example, when the terminal is connected to the charger, power is supplied all the time from the charger to the terminal. The user often wants to start the standby operation without concern for consumption of the battery. In this case, the user must make settings to start the standby operation every time he/she connects the terminal to the charger. The user may forget to make these settings.
Similarly, when the terminal is not connected to the charger, the user may want to stop the standby operation in order to suppress consumption of the battery. In this case, the user must make settings to stop the standby operation every time he/she removes the terminal from the charger. The user may forget to make these settings.
Under the circumstances, it is desired to provide a terminal and a standby operation control method, in which the convenience in standby operation of a terminal can be increased.